In a paper conveying apparatus of an image reading apparatus, image copying apparatus, etc., sometimes a jam occurs when the paper moves along the conveyance path. In general, a paper conveying apparatus is provided with the function of determining whether a jam has occurred by a paper being conveyed to a predetermined position inside the conveyance path within a predetermined time from the start of conveyance of the paper and of stopping the operation of the apparatus when a jam has occurred.
On the other hand, if a jam occurs, a large sound is generated in the conveyance path, so the paper conveying apparatus can determine whether a jam has occurred based on the sound which is generated on the conveyance path and thereby detect the occurrence of a jam without waiting for the elapse of the predetermined time.
A jam detection apparatus of a copier which converts the sound which is generated on the conveyance path to an electrical signal and determines that a jam has occurred when the time when the signal is over a reference level exceeds a reference value has been disclosed (see Japanese Laid-open Patent Publication No. 57-169767).
Further, a document scanner which acquires an image of a document in an input tray which holds the document and which optimizes the sound jam detection parameter when a wrinkle is detected has been disclosed (see U.S. Patent Publication No. 2012/0019841A).